The journal Annals of the New York Academy of Sciences did a special edition on meditation research. In one article, Dr. Travis summaries various studies on experiences of pure consciousness.
Initially this is experienced during meditation practice but soon begins to influence our sense of self. Eventually, it leads to a shift in self-identity when witnessing arises. The study refers to this as Cosmic Consciousness, although there can be stages of the development of the witness.
In a specific study (pdf), EEG patterns were compared to the subjective sense of self and inner-outer orientation. They describe this as the “Conciousness Factor”. This is related to the idea of transpersonal stages of development where the forefront of development shifts from a person to consciousness itself.
The non-meditating group were identified with thoughts, feelings, and actions. (object-referral) Short-term meditators saw themselves as the director of thoughts, feelings, and actions, a stronger sense of personal self. The long-term group saw the self as independent of and underlying thoughts, feelings, and actions. (subject-referral, transpersonal Self)
In other words, there is a correlation between certain EEG coherence factors, brain response tests and sense of self. And the regular practice of an effortless meditation develops the independent self, the platform for spiritual awakening. You can read sample responses and other test factors at the pdf link above.
Note that the mediation referred to is effortless meditation. I’ve noted prior work by Dr. Travis comparing types of mediation by their EEG signatures. Also note that “guided meditation” is not actually meditation at all but a form of hypnosis.